Semiology of subtle motor phenomena in critically ill patients

PURPOSE: to investigate the semiology of subtle motor phenomena in critically ill patients, with- versus without nonconvulsive status epilepticus (NCSE).

METHODS: 60 consecutive comatose patients, in whom subtle motor phenomena were observed in the intensive care unit (ICU), were analysed prospectively. The semiology of the subtle phenomena was described from video-recordings, blinded to all other data. For each patient, the type, location and occurrence-pattern/duration were described. EEGs recorded in the ICU were classified using the Salzburg criteria for NCSE.

RESULTS: only 23% (14/60) of the patients had NCSE confirmed by EEG. None of the semiological features could distinguish between patients with NCSE and those without. In both groups, the following phenomena were most common: discrete myoclonic muscle twitching and discrete tonic muscle activation. Besides these, automatisms and eye deviation were observed in both groups.

CONCLUSION: subtle motor phenomena in critically ill patients can raise the suspicion of NCSE. Nevertheless, EEG is needed to confirm the diagnosis, since none of the semiological features are specific.